Quantum refers to the discontinuity of events in nature

Whilst unbelief consists of logical progression from basic principles of reason, faith is not of such nature. Quantum has the notion of a jump from a quantified energy level to another.

You could consider the discontinuity in the phases of water and the idea of specific heat, for example. The phase surface has jumps in it. Virulence of bacteria is a quantum leap. Electrons jump from one energy level to another.

Faith is a leap, not necessarily associated with reason but a transfer from one knowledge base to another. Conversion could only be explained in this manner, as when a person completely leaves his former state of thinking or manner for something else. We see changes in the life of a person after his apprehension of truth.